title: Sensitive solid phase enzyme immunoassay for human IgA, secretory IgA, and secretory component.
abstract: Highly sensitive solid-phase immunoassay systems for human immunoglobulin A (IgA), secretory component (SC), secretory immunoglobulin A (SIgA) were developed by use of antisera against the alpha-chain of IgA and SC, and beta-D-galactosidase from Escherichia coli as label. IgA and SC wee assayed with the respective solid-phase (silicone rubber)-immobilized F(ab')2 antibody fragments and the corresponding antibody Fab'-beta-D-galactosidase complex. More than 1 and 0.4 fmol (or 0.16 and 0.03 ng) of IgA, and SC, respectively, were determined, but the assay system for IgA and that for SC cross-reacted with SIgA about 90% and 2%, respectively. SIgA was specifically determined in an assay using silicone rubber with immobilized (anti-alpha-chain)F(ab')2 fragments and (anti-SC) Fab'-beta-D-galactosidase complex with a minimum detectable sensitivity of 2.5 fmol or 1 ng. IgA and SC values could be corrected by subtracting the amounts of cross-reacting SIgA in the same samples. Small amounts of SIgA, SC, and IgA in saliva, sweat, urine, and feces could be determined by the present method.
mesh_terms: D002675:Child, Preschool; D005243:Feces / Q000032:analysis; D006801:Humans; D007124:Immunoenzyme Techniques; D007070:Immunoglobulin A / Q000032:analysis* / Q000652:urine; D007140:Immunoglobulin Fab Fragments; D007128:Immunoglobulin Fragments / Q000032:analysis*; D007223:Infant; D008297:Male; D012463:Saliva / Q000032:analysis; D012635:Secretory Component / Q000032:analysis* / Q000652:urine; D013542:Sweat / Q000032:analysis; D001616:beta-Galactosidase
chemical_list: D007070:Immunoglobulin A; D007140:Immunoglobulin Fab Fragments; D007128:Immunoglobulin Fragments; D012635:Secretory Component; D001616:beta-Galactosidase